hope - the thing with tests is they only really evaluate how good a person is at taking tests. It's a test-specific kind of stress, not a realistic kind of stress. If you want to test a person's skills under stress you should jump out at them from behind a corner and gauge their response .

Jumping out at someone from behind a corner is certainly a different kind of stress than taking a test. However, to say that testing creates a kind of unique "test-specific" stress which is totally useless outside a test isn't actually true. The stresses you are under in testing can be multiple (depending on the setup of the test): time pressure, fear of failure, fear of public judgment, competitive stress. Being able to demonstrate that you have automated sth to such an extent that you can be competent under these types of stress is valuable.

Performance under the stress of taking an examination does not transfer to performance under stress in the real world. Lots of literature in psychology research confirms this if you do a quick search on Google scholar.